CARDIAC SURGERY CSC CORRECT EXAMS
QUESTIONS AND ANSWERS SURE A+
✔✔You are caring for a post CABG patient who received a large amount of contrast in
the cardiac cath lab prior to going to surgery for urgent revascularization. You expect
that this patient is likely to develop which of these postoperative complications:
A. Acute kidney injury.
B. Excessive mediastinal bleeding.
C. Acute respiratory failure.
D. Ischemic stroke. - ✔✔A. Acute kidney injury (AKI) increases mortality following
cardiac surgery, and any degree of preoperative renal dysfunction greatly increases the
risk for developing AKI postoperatively. Patients who receive nephrotoxic agents, such
as large amounts of contrast during diagnostic or interventional cardiac cath
procedures, aminoglycosides, or metformin, are at increased risk for developing AKI.
Other preoperative factors that increase this risk include cardiogenic shock,
decompensated heart failure, or any preexisting renal disease. Medications that can
contribute to development of AKI include NSAIDS, ACE inhibitors, antibiotics,
furosemide, and cephalosporins. Postoperative sustained hypotension and low cardiac
output syndrome, vasoconstriction due to vasopressor drugs, renal embolization related
to IABP use, sepsis, and effects of nonpulsatile flow during CPB also increase the risk
of postoperative AKI.
Any cardiac surgery patient can develop mediastinal bleeding, respiratory failure, or
have a stroke, so the nurse must be vigilant for signs of these complications as well as
for AKI in all patients.
✔✔Which of these procedures carries the highest risk for development of acute kidney
injury (AKI) requiring dialysis:
A. Mitral valve replacement (MVR).
B. Aortic valve replacement + CABG.
C. Aortic valve replacement (AVR).
D. Mitral valve replacement (MVR) + CABG. - ✔✔D. The Society of Thoracic Surgeons
model for predicting the risk of needing dialysis after cardiac surgery assigns points for
known risk factors and uses the total point score to predict the risk of AKI requiring
dialysis. This model assigns 7 points for MVR + CABG, 5 points for AVR + CABG, 4
,points for MVR alone, and 2 points for AVR alone. CABG alone receives no points in
this model.
✔✔In the immediate postoperative period following surgery with CPB, urine output is
expected to be high:
False
True - ✔✔True
Hemodilution occurs when CBP is used which expands the extracellular volume and
produces a high urine output in the immediate postoperative period. During the first 12
hours after surgery, cardiac output may be low as the heart recovers from the effects of
CPB and surgery, which often results in transient oliguria (defined at urine output < 0.5
ml/kg/hr). Persistent oliguria usually indicates acute kidney injury.
✔✔Hypokalemia can occur after cardiac surgery because of the high urine output
associated with hemodilution during CPB. The major adverse effects of hypokalemia
after cardiac surgery are:
A. Respiratory muscle weakness delaying extubation, and cardiac arrhythmias.
B. Acute renal failure and delirium.
C. Increased incidence of stroke and delirium.
D. Increased incidence of perioperative MI and arrhythmias. - ✔✔A. Hypokalemia can
cause muscle weakness when K+ level is < 2.5 mEq/L. Respiratory muscle weakness
can delay time to extubation. Muscle weakness can also involve the GI tract and
skeletal muscles, leading to ileus and delaying ambulation. The most common
manifestation of hypokalemia is cardiac arrhythmias, including both atrial and ventricular
arrhythmias. Hypokalemia is a common cause of torsades de pointes.
Potassium level is not directly related to the incidence of perioperative MI, stroke, or
delirium.
Acute renal failure would cause hyperkalemia, not hypokalemia.
✔✔Which of the following can contribute to postoperative hyperkalemia:
A. Use of ACE inhibitors or angiotensin receptor blockers (ARBs).
B. Acute renal failure.
C. Low cardiac output state and tissue ischemia.
D. All of the above. - ✔✔D. Tissue ischemia from low cardiac output or as a
complication of IABP therapy or severe peripheral vascular disease results in cell
breakdown with release of intracellular potassium. Medications like ACE inhibitors and
ARBs result in potassium retention by the renal tubules. Acute renal failure prevents the
kidneys from excreting potassium normally. In addition, use of high potassium
cardioplegia during CPB can contribute to hyperkalemia in patients with renal
dysfunction or oliguria.
✔✔All of the following are Type I neurological complications following cardiac surgery
EXCEPT:
A. Memory loss.
B. Stroke.
,C. Coma.
D. TIA. - ✔✔A. Memory loss and varying degrees of intellectual deterioration are
classified as Type II deficits.
Type I deficits include stroke, major focal neurological deficits TIA, and coma.
CPB plays a major role in the risk for adverse neurological events, both type I and type
II, due to the resultant inflammatory response to CPB and the risk for
microembolization. Other risk factors for stroke include advanced age, atherosclerotic
aortic disease, history of stroke, hypertension, female sex, and diabetes. Additional risk
factors for type II complications include prior CABG, alcohol consumption, heart failure,
arrhythmias, and metabolic abnormalities.
✔✔Your postoperative AVR patient is confused, disoriented, sleeps during the day and
is awake all night, lethargic at times and combative at other times. This is a typical
manifestation of:
A. Acute kidney injury.
B. Acute ischemic stroke.
C. Postoperative delirium.
D. Low cardiac output syndrome. - ✔✔C. Manifestations of delirium include
disorientation, confusion, attention deficits, agitation, lethargy, disturbed sleep-wake
cycles, memory loss, paranoia, and hallucinations. These symptoms can alternate with
times of apparent lucidity
Low cardiac output states can contribute to delirium but present with hemodynamic
abnormalities, hypotension, and hypoperfusion.
Acute ischemic stroke often presents with focal deficits such as unilateral paralysis or
aphasia, although it can include some of the same symptoms as delirium.
Acute kidney injury presents with electrolyte and metabolic abnormalities, oliguria, and
often hemodynamic abnormalities which can be a cause of AKI.
✔✔Your patient had a CABG and mitral valve replacement yesterday. He has had a low
cardiac output and signs of right ventricular failure since he arrived in the ICU and is still
on the ventilator. Today he appears slightly jaundiced, his bilirubin and INR are
elevated, and serum albumin is low. This is most likely indicative of which of the
following:
A. Pain and sedation medication effect.
B. Acute respiratory failure.
C. Anticoagulation overdose.
D. Post pump hepatic dysfunction. - ✔✔D. Postoperative hepatic dysfunction can result
from reduced hepatic perfusion or from systemic congestion (usually associated with
right heart failure). Reduced hepatic perfusion can occur during CPB or postoperatively
in low cardiac output states, and is more common in patients with preexisting liver
disease, multiple comorbidities (CHF, diabetes), preoperative cardiogenic shock, and
prolonged pump time. The low serum albumin and high INR represent impaired liver
synthesis of protein and clotting factors and is a marker for hepatic dysfunction.
Pain and sedation medications can result in somnolence that prevents early extubation,
and can cause hypotension that could contribute to a low cardiac output state. However,
they would not elevate the bilirubin and INR or cause jaundice.
, Acute respiratory failure would certainly delay extubation and contribute to
postoperative problems but would not elevate the bilirubin or INR, cause jaundice, or
decrease albumin.
Anticoagulation overdose would contribute to bleeding and prolong the INR but would
not cause jaundice, elevate the bilirubin, or decrease albumin.
✔✔When caring for a patient after CABG which of the following is NOT true regarding
interventions to support stable hemodynamic status:
A. A vasodilator such as nitroprusside can help improve cardiac output when SVR is
elevated.
B. Patients will have extra fluid needs during the period of time when they are
rewarming after surgery.
C. A vasopressor such as phenylephrine will optimize cardiac output in a patient with a
cardiac index of 1.7.
D. Epicardial pacing wires can be used to increase HR and improve cardiac output. -
✔✔C. When cardiac index is low, a patient is likely to need either volume or inotropic
support. The vasopressor phenylephrine does not have positive inotropic effects.
Phenylephrine is a primary alpha-1 stimulator and causes vasoconstriction of peripheral
blood vessels. Some vasopressors such a epinephrine, dopamine, and norepinephrine
exhibit varying degrees of beta-1 stimulation (inotropic effect) in addition to alpha-1
stimulation.
Optimizing preload and heart rate are first line strategies for maintaining an adequate
cardiac output after CABG. Epicardial pacing wires can be used to maintain an
adequate heart rate when bradycardia is present.
As patients rewarm after CABG they will vasodilate and require extra fluid
administration to assure adequate preload and cardiac output.
When SVR is elevated (particularly in the presence of reduced left ventricular function)
a vasodilator such as nitroprusside can be used to decrease SVR (afterload) and
improve cardiac output.
✔✔When caring for a patient after CABG the nurse knows that the following will
increase the patient's risk for acute saphenous vein graft closure:
A. Hypothermia.
B. Hypotension or poor left ventricular function after surgery.
C. Low platelets as a result of cardiopulmonary bypass.
D. All of the above. - ✔✔B. Flow through vein grafts depends on an adequate driving
pressure through the graft, therefore patients with hypotension and decreased left
ventricular function after surgery are at increased risk for acute saphenous vein graft
closure.
Coagulopathies may develop as a result of the cardiopulmonary bypass circuit in all
patients. This increases the risk of bleeding in the postoperative period but does not
directly contribute to the risk of acute graft closure. Hypothermia also increases the risk
of bleeding but not directly to graft closure.
✔✔When caring for a patient who had the radial artery harvested during CABG surgery
the nurse is aware of the following:
QUESTIONS AND ANSWERS SURE A+
✔✔You are caring for a post CABG patient who received a large amount of contrast in
the cardiac cath lab prior to going to surgery for urgent revascularization. You expect
that this patient is likely to develop which of these postoperative complications:
A. Acute kidney injury.
B. Excessive mediastinal bleeding.
C. Acute respiratory failure.
D. Ischemic stroke. - ✔✔A. Acute kidney injury (AKI) increases mortality following
cardiac surgery, and any degree of preoperative renal dysfunction greatly increases the
risk for developing AKI postoperatively. Patients who receive nephrotoxic agents, such
as large amounts of contrast during diagnostic or interventional cardiac cath
procedures, aminoglycosides, or metformin, are at increased risk for developing AKI.
Other preoperative factors that increase this risk include cardiogenic shock,
decompensated heart failure, or any preexisting renal disease. Medications that can
contribute to development of AKI include NSAIDS, ACE inhibitors, antibiotics,
furosemide, and cephalosporins. Postoperative sustained hypotension and low cardiac
output syndrome, vasoconstriction due to vasopressor drugs, renal embolization related
to IABP use, sepsis, and effects of nonpulsatile flow during CPB also increase the risk
of postoperative AKI.
Any cardiac surgery patient can develop mediastinal bleeding, respiratory failure, or
have a stroke, so the nurse must be vigilant for signs of these complications as well as
for AKI in all patients.
✔✔Which of these procedures carries the highest risk for development of acute kidney
injury (AKI) requiring dialysis:
A. Mitral valve replacement (MVR).
B. Aortic valve replacement + CABG.
C. Aortic valve replacement (AVR).
D. Mitral valve replacement (MVR) + CABG. - ✔✔D. The Society of Thoracic Surgeons
model for predicting the risk of needing dialysis after cardiac surgery assigns points for
known risk factors and uses the total point score to predict the risk of AKI requiring
dialysis. This model assigns 7 points for MVR + CABG, 5 points for AVR + CABG, 4
,points for MVR alone, and 2 points for AVR alone. CABG alone receives no points in
this model.
✔✔In the immediate postoperative period following surgery with CPB, urine output is
expected to be high:
False
True - ✔✔True
Hemodilution occurs when CBP is used which expands the extracellular volume and
produces a high urine output in the immediate postoperative period. During the first 12
hours after surgery, cardiac output may be low as the heart recovers from the effects of
CPB and surgery, which often results in transient oliguria (defined at urine output < 0.5
ml/kg/hr). Persistent oliguria usually indicates acute kidney injury.
✔✔Hypokalemia can occur after cardiac surgery because of the high urine output
associated with hemodilution during CPB. The major adverse effects of hypokalemia
after cardiac surgery are:
A. Respiratory muscle weakness delaying extubation, and cardiac arrhythmias.
B. Acute renal failure and delirium.
C. Increased incidence of stroke and delirium.
D. Increased incidence of perioperative MI and arrhythmias. - ✔✔A. Hypokalemia can
cause muscle weakness when K+ level is < 2.5 mEq/L. Respiratory muscle weakness
can delay time to extubation. Muscle weakness can also involve the GI tract and
skeletal muscles, leading to ileus and delaying ambulation. The most common
manifestation of hypokalemia is cardiac arrhythmias, including both atrial and ventricular
arrhythmias. Hypokalemia is a common cause of torsades de pointes.
Potassium level is not directly related to the incidence of perioperative MI, stroke, or
delirium.
Acute renal failure would cause hyperkalemia, not hypokalemia.
✔✔Which of the following can contribute to postoperative hyperkalemia:
A. Use of ACE inhibitors or angiotensin receptor blockers (ARBs).
B. Acute renal failure.
C. Low cardiac output state and tissue ischemia.
D. All of the above. - ✔✔D. Tissue ischemia from low cardiac output or as a
complication of IABP therapy or severe peripheral vascular disease results in cell
breakdown with release of intracellular potassium. Medications like ACE inhibitors and
ARBs result in potassium retention by the renal tubules. Acute renal failure prevents the
kidneys from excreting potassium normally. In addition, use of high potassium
cardioplegia during CPB can contribute to hyperkalemia in patients with renal
dysfunction or oliguria.
✔✔All of the following are Type I neurological complications following cardiac surgery
EXCEPT:
A. Memory loss.
B. Stroke.
,C. Coma.
D. TIA. - ✔✔A. Memory loss and varying degrees of intellectual deterioration are
classified as Type II deficits.
Type I deficits include stroke, major focal neurological deficits TIA, and coma.
CPB plays a major role in the risk for adverse neurological events, both type I and type
II, due to the resultant inflammatory response to CPB and the risk for
microembolization. Other risk factors for stroke include advanced age, atherosclerotic
aortic disease, history of stroke, hypertension, female sex, and diabetes. Additional risk
factors for type II complications include prior CABG, alcohol consumption, heart failure,
arrhythmias, and metabolic abnormalities.
✔✔Your postoperative AVR patient is confused, disoriented, sleeps during the day and
is awake all night, lethargic at times and combative at other times. This is a typical
manifestation of:
A. Acute kidney injury.
B. Acute ischemic stroke.
C. Postoperative delirium.
D. Low cardiac output syndrome. - ✔✔C. Manifestations of delirium include
disorientation, confusion, attention deficits, agitation, lethargy, disturbed sleep-wake
cycles, memory loss, paranoia, and hallucinations. These symptoms can alternate with
times of apparent lucidity
Low cardiac output states can contribute to delirium but present with hemodynamic
abnormalities, hypotension, and hypoperfusion.
Acute ischemic stroke often presents with focal deficits such as unilateral paralysis or
aphasia, although it can include some of the same symptoms as delirium.
Acute kidney injury presents with electrolyte and metabolic abnormalities, oliguria, and
often hemodynamic abnormalities which can be a cause of AKI.
✔✔Your patient had a CABG and mitral valve replacement yesterday. He has had a low
cardiac output and signs of right ventricular failure since he arrived in the ICU and is still
on the ventilator. Today he appears slightly jaundiced, his bilirubin and INR are
elevated, and serum albumin is low. This is most likely indicative of which of the
following:
A. Pain and sedation medication effect.
B. Acute respiratory failure.
C. Anticoagulation overdose.
D. Post pump hepatic dysfunction. - ✔✔D. Postoperative hepatic dysfunction can result
from reduced hepatic perfusion or from systemic congestion (usually associated with
right heart failure). Reduced hepatic perfusion can occur during CPB or postoperatively
in low cardiac output states, and is more common in patients with preexisting liver
disease, multiple comorbidities (CHF, diabetes), preoperative cardiogenic shock, and
prolonged pump time. The low serum albumin and high INR represent impaired liver
synthesis of protein and clotting factors and is a marker for hepatic dysfunction.
Pain and sedation medications can result in somnolence that prevents early extubation,
and can cause hypotension that could contribute to a low cardiac output state. However,
they would not elevate the bilirubin and INR or cause jaundice.
, Acute respiratory failure would certainly delay extubation and contribute to
postoperative problems but would not elevate the bilirubin or INR, cause jaundice, or
decrease albumin.
Anticoagulation overdose would contribute to bleeding and prolong the INR but would
not cause jaundice, elevate the bilirubin, or decrease albumin.
✔✔When caring for a patient after CABG which of the following is NOT true regarding
interventions to support stable hemodynamic status:
A. A vasodilator such as nitroprusside can help improve cardiac output when SVR is
elevated.
B. Patients will have extra fluid needs during the period of time when they are
rewarming after surgery.
C. A vasopressor such as phenylephrine will optimize cardiac output in a patient with a
cardiac index of 1.7.
D. Epicardial pacing wires can be used to increase HR and improve cardiac output. -
✔✔C. When cardiac index is low, a patient is likely to need either volume or inotropic
support. The vasopressor phenylephrine does not have positive inotropic effects.
Phenylephrine is a primary alpha-1 stimulator and causes vasoconstriction of peripheral
blood vessels. Some vasopressors such a epinephrine, dopamine, and norepinephrine
exhibit varying degrees of beta-1 stimulation (inotropic effect) in addition to alpha-1
stimulation.
Optimizing preload and heart rate are first line strategies for maintaining an adequate
cardiac output after CABG. Epicardial pacing wires can be used to maintain an
adequate heart rate when bradycardia is present.
As patients rewarm after CABG they will vasodilate and require extra fluid
administration to assure adequate preload and cardiac output.
When SVR is elevated (particularly in the presence of reduced left ventricular function)
a vasodilator such as nitroprusside can be used to decrease SVR (afterload) and
improve cardiac output.
✔✔When caring for a patient after CABG the nurse knows that the following will
increase the patient's risk for acute saphenous vein graft closure:
A. Hypothermia.
B. Hypotension or poor left ventricular function after surgery.
C. Low platelets as a result of cardiopulmonary bypass.
D. All of the above. - ✔✔B. Flow through vein grafts depends on an adequate driving
pressure through the graft, therefore patients with hypotension and decreased left
ventricular function after surgery are at increased risk for acute saphenous vein graft
closure.
Coagulopathies may develop as a result of the cardiopulmonary bypass circuit in all
patients. This increases the risk of bleeding in the postoperative period but does not
directly contribute to the risk of acute graft closure. Hypothermia also increases the risk
of bleeding but not directly to graft closure.
✔✔When caring for a patient who had the radial artery harvested during CABG surgery
the nurse is aware of the following:
